Page({
  data: {
    ctx: null,
    width: null,
    height: null,
    drawCount: 0,
    drawState: "init"
  },
  onShow: function () {
    this.initCanvas()
  },
  initCanvas() {
    let {
      width,
      height
    } = this.data
    width = wx.getSystemInfoSync().windowWidth
    height = wx.getSystemInfoSync().windowHeight
    console.log(wx.getSystemInfoSync())
    this.data.ctx = wx.createCanvasContext('canvas')
    this.setData({
      width,
      height
    })
    this.handleClearCanvas()
  },
  handleClearCanvas() {
    this.data.drawCount = 0
    this.data.drawState = "ing"
    this.data.ctx.setTextBaseline('top')
    this.data.ctx.setTextAlign('center')
    this.data.ctx.setFontSize(20)
    this.data.ctx.setFillStyle('#616165');
    this.data.ctx.fillText("请灰色区域内完成签名", this.data.width / 2, 30)
    this.data.ctx.draw(false)
  },
  handleCatchtouchstart(e) {
    if (this.data.drawCount == 0) {
      this.data.ctx.draw(false)
    }
    this.data.drawCount++
    this.data.ctx.moveTo(e.changedTouches[0].clientX, e.changedTouches[0].clientY)
  },
  handleCatchtouchend(e) {
    this.data.points = []
  },
  handleCatchtouchmove(e) {
    if (this.data.drawState == "stop") return
    this.data.drawState = "ing"
    if (e.touches.length > 1) {
      return
    }
    this.data.ctx.setStrokeStyle('#000000');
    this.data.ctx.setLineWidth(3);
    this.data.ctx.setShadow(0, 0, 0.5, '#000000')
    this.data.ctx.setLineCap('round');
    this.data.ctx.setLineJoin('round');
    this.data.ctx.lineTo(e.changedTouches[0].clientX, e.changedTouches[0].clientY)
    this.data.ctx.stroke()
    this.data.ctx.draw(true)
    this.data.ctx.moveTo(e.changedTouches[0].clientX, e.changedTouches[0].clientY)
  },
  handleCanvasToImg() {
    if (this.data.drawState == "init") return
    this.data.drawState = "stop"
    wx.canvasToTempFilePath({
      canvasId: 'canvas',
      success: res => {
        console.log(res.tempFilePath)
      }
    })
  }
})
